[amsat-bb] Re: Dutch Transponder on-baord HAMSAT VO-52 'Turned On'

[i8cvs]

Hi Greg, KO6TH

In my opinion one lesson the satellite community can learn from this,
is that if we want to communicate a satellites should be designed with
only one mode and with redundant transponders i.e. "strong and stupid"

BTW after working few orbits it seems to me that the indian transponder
was less subject to be overloaded in comparison to the Dutch transponder.

If the EIRP is too high and there are many station in the passband the
Dutch transponder is FMing and get distorted while the indian transponder
was more linear and less subject to be overloaded.

If the uplink power is in the order of 10 to 20 watt into a 10 dBi RHCP
antenna than the Dutch transponder is not overloaded.

I agree with you that it will be very interesting to know from ISRO if the
difference in linearity between the above transponders is due to the actual
battery conditions or to a different performance of the AGC

73" de

i8CVS Domenico

----- Original Message -----
From: "Greg D" <ko6th.greg at gmail.com>
To: "Mani VU2WMY" <wmy at isac.gov.in>
Cc: "RANGAN" <tprangan at istrac.org>; "AMSAT-INDIA"
<amsatindia at yahoogroups.com>; "VUHAMS" <vuhams at yahoogroups.com>; "PE1RAH"
<pe1rah at yahoo.com>; "BB,AMSAT" <amsat-bb at amsat.org>; "VU3TYG"
<vu3tyg at yahoo.co.in>
Sent: Thursday, March 15, 2012 4:05 AM
Subject: [amsat-bb] Re: Dutch Transponder on-baord HAMSAT VO-52 'Turned On'


> Hi Mani,
>
> Congratulations on the recovery of VO-52; it's great to have our friend
> back.
>
> I am curious if ISRO will be issuing some sort of report on what
> happened. I understand that they will have limits on what they can say,
> but if there is something the satellite community can learn from this,
> it would be good to not miss the opportunity.
>
> Greg KO6TH
>
>
> Mani VU2WMY wrote:
> > Dear HAMSAT VO-52 users,
> > The commands to 'Turn On' the transponder # 2 (Dutch transponder, made
> > by Williams PE1RAH) on-board HAMSAT VO-52 was successfully sent during
> > 14:00 UT 35 deg ascending Node pass over Bangalore, India.
> >
> > The sent commands were successfully received, acknowledged and
> > confirmed by the telemetry. Subsequently, the transponder # 2 is now
> > 'ON' and Williams CW message beacon was heard again after a gap of
> > approximately 6 years & 4 months.
> >
> > The beacon signal was heard loud and strong here at Bangalore.
> >
> >
> >
> > A detailed Initial reports addressed to:
> > tprangan at istrac.org
> > and a copy to
> > wmy at isac.gov.in
> > would be greatly appreciated.
> >
> >
> > 73 de
> >
> > Mani, VU2WMY
> > Secretary & Station-In-Charge
> > Upagrah Amateur Radio Club VU2URC
> > ISRO Satellite Centre
> > HAL Airport Road, Bangalore-560 017.
> > Phone:(O)91-80-25082054/2598/2192
> > Mobile: 91-80-98803 41456
> > E-mail ID: wmy at isac.gov.in
> > vu2wmy_mani at yahoo.com
> > isrohams at yahoo.com
> >
> >
>
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